This proposal described the organization of a comprehensive HIV Vaccine Trials Network (HVTN). The proposal is submitted in 3 sections: a) a Vaccine Leadership Group (VLG) core proposal, L. Corey Principal Investigator (PI), b) a Statistical Data Management Proposal, S. Self, PI, and c) a Laboratory Science Proposal, D. Bolognesi PI. The objective of the VLG is to establish an organizational structure that will direct a clinical trials network that will efficiently conduct Phase I, Phase II, and Phase III clinical trials of candidate HIV-1 vaccines in both the United States and International settings. As compared to the current NIAID HIV vaccine clinical trials network, the scientific emphasis of the HVTN will include more rapid development of candidate vaccines for international trials, a more focused laboratory-based program on immune responses to HIV-1 vaccines, and studies of correlates of protection in vaccine efficacy trials. The HVTN will be led by an 11 member Scientific Steering Committee. In addition, an External Advisory Committee of senior investigators experienced in HIV pathogenesis and vaccine development will provide fiscal and programmatic oversight to the leadership. The organizational structure of the HVTN will include 4 scientific committees (Phase I/IIA, Phase III, Laboratory Sciences Committee, and International Trials Committee) a National Community Advisory Board, a Clinical Coordinators Committee, and 4 working groups dedicated to 1) Primary HIV Infection, 2) Maternal-Adolescent Immunization, 3) Non-human Primate Studies, and 4) International Clinical Trials Coordination. A Core Statistical Data Management Center, an Operations Center, and Core Laboratories are also associated with the HVTN. The research agenda of the HVTN will focus upon: 1) developing vaccines with immune responses to circulating R5 viruses, 2) the development of reproducible quantitative assays to evaluate cellular responses to HIV vaccines, 3) the impact of vaccination on attenuation of infection, pathogenesis and transmission of HIV infection, 4) establishment of a close link between vaccine studies in humans and in nonhuman primate models, and 5) developing a clinical trails program that will be proactive in evaluating novel vaccine candidates both in domestic and international trial sites. Responsibilities of the new network include developing a smooth transition plan between the current AVEG and HIVNET vaccine program, as well as initiating the first NIAID sponsored HIV-1 vaccine efficacy trial scheduled for September 2000. Over 30 senior investigators are involved in the proposal network. These investigators and their laboratories have extensive experience in the design, conduct and analyses of vaccine trials in both the United States and Internationally.